Hcfo-containing isocyanate-reactive compositions, related foam-forming compositions and flame retardant pur-pir foams

ABSTRACT

HCFO-containing isocyanate-reactive compositions, foam-forming compositions containing such isocyanate-reactive compositions, rigid PUR-PIR foams made using such foam-forming compositions, and methods for producing such foams, including use of such foams as insulation in discontinuous foam panel applications. The isocyanate-reactive composition includes a polyol blend, a blowing agent composition, and a tertiary amine catalyst. The polyol blend includes: (1) an aromatic polyester polyol having a functionality of 1.5 to less than 2.5 and an OH number of 150 to 360 mg KOH/g; (2) an aromatic polyester polyol having a functionality of at least 2.5 and an OH number greater than 360 mg KOH/g, which is present in an amount of at least 10% by weight, based on the total weight of the aromatic polyester polyol in the polyol blend; and (3) an amine-initiated polyether polyol having an OH number of at least 500 mg KOH/g and a functionality of 2.5 to 4. The blowing agent composition includes a hydrochlorofluoroolefin and a carbon dioxide generating chemical blowing agent.

FIELD

This specification pertains generally to hydrochlorofluoroolefin(“HCFO”)-containing isocyanate-reactive compositions, foam-formingcompositions containing such isocyanate-reactive compositions, rigidfoams made using such foam-forming compositions, and methods forproducing such foams, including use of such foams as panel insulation.

BACKGROUND

Flame-retardant rigid polyurethane foams are used in numerousindustries. They are produced by reacting an appropriate polyisocyanateand an isocyanate-reactive compound, usually a polyol, in the presenceof a blowing agent and catalysts to produce polyisocyanurate-containingand polyurethane-containing foams. One use of such foams is as a thermalinsulation medium in the construction of panel assemblies, such asdoors, including garage doors. The thermal insulating properties ofclosed-cell rigid foams are dependent upon a number of factors,including the average cell size and the thermal conductivity of thecontents of the cells.

Chlorofluorocarbons (CFC's) and hydrogen-containing chlorofluorocarbons(HCFC's) have been used as blowing agents to produce these foams becauseof their exceptionally low vapor thermal conductivity. However, theirozone-depletion potential is a drawback to their use. Alternativeblowing agents, such as hydrofluorocarbons (HFC's) are also used, butthey are greenhouse gases. Hydrocarbons, such as pentane isomers, havealso been used, but these are flammable and have lower energyefficiency. Halogenated hydroolefinic compounds, such as HCFOs, are nowreplacements for HFCs, since their chemical instability in the loweratmosphere provides for a low global warming potential and zero or nearzero ozone depletion properties.

Formulations used to produce thermally insulating rigid polyurethanefoam, particularly those used in the construction of panel assemblies,utilize catalysts to control the relative rates of water-polyisocyanate(gas-forming or blowing), the polyol-polyisocyanate (gelling) reactionto form polyurethane (“PUR”), and the isocyanate-isocyanatetrimerization reaction to form polyisocyanurate (“PIR”). In the gellingreaction, the isocyanate reacts with polyols to form the polyurethanefoam matrix. In the trimerization reaction, isocyanates react with oneanother to form macromolecules with isocyanurate structures(polyisocyanurates). In the blowing reaction, the isocyanate reacts withwater in the formulation to form polyurea and carbon dioxide. Whilethese reactions take place at different rates, it is necessary toproperly balance them to produce high-quality foam. For example, if theblowing reaction occurs faster than the gelling reaction, the gasgenerated by the reaction may expand before the polyurethane matrix isstrong enough to contain it and foam collapse can occur. In contrast, ifthe gelling reaction occurs faster than the blowing reaction, the foamcells will remain closed, causing the foam to shrink as it cools.Moreover, if the gelling reaction occurs while the reaction mixture isstill flowing, cell stretching may occur, resulting in elongated cellstructures. Foams with such elongated cell structures generally exhibitpoorer physical properties, such as poorer compressive strength, poorerdimensional stability (more foam shrinkage), poorer thermal insulationproperties, and poorer foam quality (due to surface voids and otherdefects).

As a result, to achieve the proper balance, formulations often utilize acombination of blow catalysts, gel catalysts, and/or trimerizationcatalysts. Amine catalysts, for example, are known to have a greatereffect on the water-polyisocyanate blowing reaction, whereas organotincatalysts are known to have a greater effect on thepolyol-polyisocyanate gelling reaction.

A drawback to at least some HCFOs as blowing agents in the production ofsatisfactory isocyanate-based foams is poor shelf-life. Blowing agentsoften are combined with polyols and other components, such assurfactant(s) and the catalyst(s), to form a so-called “B-side” pre-mixthat may be stored for up to several months prior to being combined withan “A-side” isocyanate component to form the foam.

With certain HCFOs, however, if the B-side composition is aged prior tocombining with the polyisocyanate, the foam can be of lower quality andmay even collapse during the formation of foam. The poor foam structureis thought to be attributable to the reaction of certain catalysts,particularly amine catalysts, with these HCFOs which results in thepartial decomposition of the blowing agent and, as a result, undesirablemodification of silicone surfactants, resulting in poor foam structureand quality.

To combat this issue, certain amine catalysts have been identified thatcan exhibit substantially improved stability with HCFOs. Such catalysts,however, are not without some drawbacks. In addition to being relativelycostly, they tend to be weak catalysts, thereby necessitating their usein relatively high loadings, which both amplifies the cost impact andlimits the ability of a foam formulator to optimize the foam flowprofile and quality. As a result, it would be desirable to identify waysto reduce the amount of such amine catalysts that are required in aformulation.

Foam-forming compositions used in the production of certain panelassemblies, particularly those produced in a discontinuous open andclosed pour processes must exhibit a stringent combination ofproperties. For example, in addition to possessing good thermalinsulation properties, in some cases a K-factor of 0.125 BTU-in/h-ft²-°F. or lower, many foams must pass Class A E84 burn requirements forsmoke and flame spread. To achieve this, the foam must exhibit a flamespread index (FSI) of 25 or less and a smoke-developed index (SDI) of450 or less according to ASTM E84-21 at the applied foam thickness. Theyalso must exhibit target cream and gel times conducive to themanufacturing equipment and process that is used, and they must exhibita long shelf life, which means that this gel time cannot change by alarge amount after storage of the foam-forming composition componentsfor a long period of time (several months or more), even when a chemicalblowing agent, such as water, is also used. The isocyanate-reactivecomposition used must also be phase stable in that it does do notexhibit any significant phase separation over time. The foams also mustexhibit good dimensional stability (low foam shrinkage) even when thefree-rise foams have a density of less than 2.0 lb/ft³. A compositionthat can fulfill most, if not all, of these requirements, whileutilizing a HCFO blowing agent would, therefore, before highlydesirable.

SUMMARY

In certain respects, the present disclosure is directed toisocyanate-reactive compositions. These compositions comprise: (a) apolyol blend, (b) a blowing agent composition, and (c) a tertiary aminecatalyst. The polyol blend comprises: (1) an aromatic polyester polyolhaving a functionality of 1.5 to less than 2.5 and an OH number of 150to 360 mg KOH/g; (2) an aromatic polyester polyol having a functionalityof at least 2.5 and an OH number greater than 360 mg KOH/g, which ispresent in an amount of at least 10% by weight, based on the totalweight of the aromatic polyester polyol in the polyol blend; and (3) anamine-initiated polyether polyol having an OH number of at least 500 mgKOH/g and a functionality of 2.5 to 4. Aromatic polyester polyol ispresent in an amount of at least 50% by weight, based on the totalweight of the polyol blend. The blowing agent composition comprises aphysical blowing agent comprising a hydrochlorofluoroolefin and a carbondioxide generating chemical blowing agent.

The present specification is also directed to foam-forming compositionsthat include such isocyanate-reactive compositions, rigid PUR-PIR foamsproduced from such foam-forming compositions, methods for making suchrigid foams, and composite articles comprising such rigid foams, andpanel insulation that includes such rigid foams.

DETAILED DESCRIPTION

Various implementations are described and illustrated in thisspecification to provide an overall understanding of the structure,function, properties, and use of the disclosed inventions. It isunderstood that the various implementations described and illustrated inthis specification are non-limiting and non-exhaustive. Thus, theinvention is not limited by the description of the various non-limitingand non-exhaustive implementations disclosed in this specification. Thefeatures and characteristics described in connection with variousimplementations may be combined with the features and characteristics ofother implementations. Such modifications and variations are intended tobe included within the scope of this specification. As such, the claimsmay be amended to recite any features or characteristics expressly orinherently described in, or otherwise expressly or inherently supportedby, this specification. Further, Applicant(s) reserve the right to amendthe claims to affirmatively disclaim features or characteristics thatmay be present in the prior art. Therefore, any such amendments complywith the requirements of 35 U.S.C. § 112 and 35 U.S.C. § 132(a). Thevarious implementations disclosed and described in this specificationcan comprise, consist of, or consist essentially of the features andcharacteristics as variously described herein.

Any patent, publication, or other disclosure material identified hereinis incorporated by reference into this specification in its entiretyunless otherwise indicated, but only to the extent that the incorporatedmaterial does not conflict with existing definitions, statements, orother disclosure material expressly set forth in this specification. Assuch, and to the extent necessary, the express disclosure as set forthin this specification supersedes any conflicting material incorporatedby reference herein. Any material, or portion thereof, that is said tobe incorporated by reference into this specification, but whichconflicts with existing definitions, statements, or other disclosurematerial set forth herein, is only incorporated to the extent that noconflict arises between that incorporated material and the existingdisclosure material. Applicant(s) reserves the right to amend thisspecification to expressly recite any subject matter, or portionthereof, incorporated by reference herein.

In this specification, other than where otherwise indicated, allnumerical parameters are to be understood as being prefaced and modifiedin all instances by the term “about”, in which the numerical parameterspossess the inherent variability characteristic of the underlyingmeasurement techniques used to determine the numerical value of theparameter. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter described in the present description should atleast be construed in light of the number of reported significant digitsand by applying ordinary rounding techniques.

Also, any numerical range recited in this specification is intended toinclude all sub-ranges of the same numerical precision subsumed withinthe recited range. For example, a range of “1.0 to 10.0” is intended toinclude all sub-ranges between (and including) the recited minimum valueof 1.0 and the recited maximum value of 10.0, that is, having a minimumvalue equal to or greater than 1.0 and a maximum value equal to or lessthan 10.0, such as, for example, 2.4 to 7.6. Any maximum numericallimitation recited in this specification is intended to include alllower numerical limitations subsumed therein and any minimum numericallimitation recited in this specification is intended to include allhigher numerical limitations subsumed therein. Accordingly, Applicant(s)reserves the right to amend this specification, including the claims, toexpressly recite any sub-range subsumed within the ranges expresslyrecited herein. All such ranges are intended to be inherently describedin this specification such that amending to expressly recite any suchsub-ranges would comply with the requirements of 35 U.S.C. § 112 and 35U.S.C. § 132(a).

The grammatical articles “one”, “a”, “an”, and “the”, as used in thisspecification, are intended to include “at least one” or “one or more”,unless otherwise indicated. Thus, the articles are used in thisspecification to refer to one or more than one (i.e., to “at least one”)of the grammatical objects of the article. By way of example, “acomponent” means one or more components, and thus, possibly, more thanone component is contemplated and may be employed or used in animplementation of the described implementations. Further, the use of asingular noun includes the plural, and the use of a plural noun includesthe singular, unless the context of the usage requires otherwise.

As used herein, the term “functionality” refers to the average number ofreactive hydroxyl groups, —OH, present per molecule of the —OHfunctional material that is being described. In the production ofpolyurethane foams, the hydroxyl groups react with isocyanate groups,—NCO, that are attached to the isocyanate compound. The term “hydroxylnumber” refers to the number of reactive hydroxyl groups available forreaction, and is expressed as the number of milligrams of potassiumhydroxide equivalent to the hydroxyl content of one gram of the polyol(ASTM D4274-16). The term “equivalent weight” refers to the weight of acompound divided by its valence. For a polyol, the equivalent weight isthe weight of the polyol that will combine with an isocyanate group, andmay be calculated by dividing the molecular weight of the polyol by itsfunctionality. The equivalent weight of a polyol may also be calculatedby dividing 56,100 by the hydroxyl number of the polyol−EquivalentWeight (g/eq)=(56.1×1000)/OH number.

As indicated, certain implementations of the present specificationrelate to isocyanate-reactive compositions useful in the production ofrigid foams. A rigid foam is characterized as having a ratio ofcompressive strength to tensile strength of at least 0.5:1, elongationof less than 10%, as well as a low recovery rate from distortion and alow elastic limit, as described in in “Polyurethanes: Chemistry andTechnology, Part II Technology,” J. H. Saunders & K. C. Frisch,Interscience Publishers, 1964, page 239.

The rigid foams of this specification are the reaction product of apolyurethane-foam forming composition that includes: (a) apolyisocyanate; and (b) an isocyanate-reactive composition. As usedherein, the term “polyisocyanate” encompasses diisocyanates and otherisocyanates having more than one isocyanate (—NCO) functional group permolecule.

Any of the known organic isocyanates, modified isocyanates orisocyanate-terminated prepolymers made from any of the known organicisocyanates may be used. Suitable organic isocyanates include aromatic,aliphatic, and cycloaliphatic polyisocyanates and combinations thereof.Useful isocyanates include: diisocyanates such as m-phenylenediisocyanate, p-phenylene diisocyanate, 2,4-toluene diisocyanate,2,6-toluene diisocyanate, 1,6-hexamethylene diisocyanate,1,4-hexamethylene diisocyanate, 1,3-cyclohexane diisocyanate,1,4-cyclo-hexane diisocyanate, isomers of hexahydro-toluenediisocyanate, isophorone diisocyanate, dicyclo-hexylmethanediisocyanates, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethanediisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-biphenylenediisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate and3,3′-dimethyl-diphenyl-propane-4,4′-diisocyanate; triisocyanates such as2,4,6-toluene triisocyanate; and polyisocyanates such as4,4′-dimethyl-diphenylmethane-2,2′,5,5′-tetraisocyanate and thepolymethylene polyphenyl-polyisocyanates.

Undistilled or crude polyisocyanates may also be used. The crude toluenediisocyanate obtained by phosgenating a mixture of toluene diamines andthe crude diphenylmethane diisocyanate obtained by phosgenating crudediphenylmethanediamine (polymeric MDI) are examples of suitable crudepolyisocyanates. Suitable undistilled or crude polyisocyanates aredisclosed in U.S. Pat. No. 3,215,652.

Modified isocyanates are obtained by chemical reaction of diisocyanatesand/or polyisocyanates. Useful modified isocyanates include, but are notlimited to, those containing ester groups, urea groups, biuret groups,allophanate groups, carbodiimide groups, isocyanurate groups, uretdionegroups and/or urethane groups. Examples of modified isocyanates includeprepolymers containing NCO groups and having an NCO content of from 25to 35 weight percent, such as from 29 to 34 weight percent, such asthose based on polyether polyols or polyester polyols anddiphenylmethane diisocyanate.

In certain implementations, the polyisocyanate comprises amethylene-bridged polyphenyl polyisocyanate and/or a prepolymer ofmethylene-bridged polyphenyl polyisocyanates having an averagefunctionality of from 1.8 to 3.5, such as from 2.0 to 3.1, isocyanatemoieties per molecule and an NCO content of from 25 to 32 weightpercent, due to their ability to cross-link the polyurethane.

The isocyanate-reactive compositions described in this specificationcomprise a polyol blend. More specifically, the polyol blend comprisesat least two different aromatic polyester polyols comprising: (1)aromatic polyester polyol having a functionality of 1.5 to less than 2.5and an OH number of 150 to 360 mg KOH/g; and (2) an aromatic polyesterpolyol having a functionality of at least 2.5 and an OH number greaterthan 360 mg KOH/g, with aromatic polyester polyol (2) being present inan amount of at least 10% by weight, based on the total weight ofaromatic polyester polyol that is in the polyol blend.

Suitable such aromatic polyester polyols include, for example, thereaction product of an aromatic diacid or anhydride with a suitableglycol and/or triol. For example, polyester polyols can be the reactionproduct of a glycol and/or triol, such as ethylene glycol, propyleneglycol, butylene glycol, 1,3-butanediol, neopentyl glycol, diethyleneglycol, dipropylene glycol, triethylene glycol, tripropylene glycol,glycerol, trimethylolethane, trimethyolpropane, pentanediol, hexanediol,heptanediol, 1,3- and 1,4-dimethylol cyclohexane, or a mixture of anytwo or more thereof with an aromatic diacid or aromatic anhydride, suchas, for example, phthalic acid, isophthalic acid, terephthalic acid,phthalic anhydride, or a mixture of any two or more thereof. Some ofexamples of the suitable aromatic polyester polyols include thosecompounds which are available from Stepan Chemical under the Stepanpoltrade name such as, for example, Stepanpol® PS 3024 and Stepanpol PS2502A or from Invista under the Terate trade name, such as Terate®HT-5100 and HT-5500, or from Coim under the Isoexter trade name such asIsoexter® TB-375.

In some implementations, aromatic polyester polyol (1), which has afunctionality of 1.5 to less than 2.5 and an OH number of 150 to 360 mgKOH/g, has an OH number of 200 to 335 mg KOH/g, or, in some cases, 200to 250 mg KOH/g, and a functionality of 1.8 to less than 2.5, such as1.8 to 2.2 or 1.9 to 2.1. In some implementations, aromatic polyesterpolyol (2), which has a functionality of at least 2.5 and an OH numbergreater than 360 mg KOH/g, has an OH number of greater than 360 to 500mg KOH/g, greater than 360 to 400 mg KOH/g, or, in some cases, 365 to385 mg KOH/g, and a functionality of 2.5 to 3.5, such as 2.8 to 3.2 or2.9 to 3.1, or 3.0.

In the isocyanate-reactive compositions of this specification, thearomatic polyester polyol is present in an amount of at least 50% byweight, based on the total weight of the polyol blend. In someimplementations, aromatic polyester polyol is present in an amount of 50to 85% by weight, such as 50 to 70% by weight, 55 to 65% by weight, or,in some cases, 55 to 60% by weight, based on the total weight of theisocyanate-reactive composition. In some implementations, aromaticpolyester polyol present in an amount of 50 to 95% by weight, 70 to 90%by weight, or, in some cases 80 to 90% by weight, based on total weightof polyol blend that is in the isocyanate-reactive composition. In someimplementations, aromatic polyester polyol (1) and aromatic polyesterpolyol (2) are present in the polyol blend in a relative ratio, byweight, of 0.5:1.0 to 2.0:1.0, such as 0.5:1.0 to 1.5:1.0, or 0.8:1.0 to1.2:1.0, or, in some cases, 1.0:1.0 to 1.2:1.0.

The polyol blend further comprises an amine-initiated polyether polyol,such as an alkanolamine-initiated polyether polyol. As used herein,“alkanolamine-initiated polyether polyol” refers to a polyether polyolprepared by reacting at least one alkylene oxide with one or moresuitable starter compounds in the presence of a suitable catalyst, inwhich the starter compounds comprise one or more alkanolamines. Suitablecatalysts including basic catalysts (such as sodium or potassiumhydroxide or tertiary amines such as methyl imidazole) and DMCcatalysts.

As used herein, the term “alkanolamine” refers to compounds representedby the formula:

NH₂—Z—OH

in which Z represents a divalent radical which is a straight chain orbranched chain alkylene radical having 2 to 6 carbon atoms, acycloalkylene radical having 4 to 6 carbon atoms or a dialkylene etherradical having 4 to 6 carbon atoms. The dialkylene ether radical may berepresented by the formula:

R—O—R—

where each R represents a hydrocarbon radical having 2 to 3 carbonatoms.

Specific examples of suitable alkanolamines that may be used in thepreparation of the alkanolamine-initiated polyether polyol includemonoethanolamine, 1-amino-2-propanol, 2-amino-1-propanol,3-amino-1-propanol, 1-(2-aminoethoxy) ethanol, 1-amino-2-butanol,2-amino-3-butanol, 2-amino-2-methylpropanol, 5-amino pentanol,3-amino-2, 2-dimethyl propanol, 4-aminocyclohexanol, as well as mixturesof any two or more thereof.

To prepare the alkanolamine-initiated polyether polyol, the alkanolamineis reacted with an alkylene oxide. Suitable alkylene oxides includeethylene oxide, propylene oxide, butylene oxide, styrene oxide, andepichlorohydrin, as well as mixtures of any two or more thereof.

In some implementations, the amine-initiated, such asalkanolamine-initiated, polyether polyol has an OH number of at least500 mg KOH/g, such as 500 to 900 mg KOH/g, such as 600 to 800 mg KOH/g,or, in some cases, 680 to 720 mg KOH/g, and a functionality of 2.5 to 4,such as 2.5 to 3.5.

In some implementations, the amine-initiated, such asalkanolamine-initiated, polyether polyol is utilized in an amount of 0.1to 10% by weight, such as 1 to 10% by weight or 2 to 6% by weight, basedupon the total weight of the polyol blend that is in theisocyanate-reactive composition. In some implementations, theamine-initiated, such as alkanolamine-initiated, polyether polyol ispresent in an amount of 0.1 to 10% by weight, 0.1 to 5% by weight, or,in some cases 1 to 5% by weight, based on the total weight of theisocyanate-reactive composition. In certain implementations, aromaticpolyester polyol and amine-initiated, such as alkanolamine-initiated,polyether polyol are present in the polyol blend in a weight ratio of atleast 10:1, such as 10:1 to 50:1, or, in some cases 10:1 to 30:1 or 15:1to 25:1.

The polyol blend may, and often does, include additional polyols. Forexample, in some implementations, the polyol blend comprises asaccharide-initiated polyether polyol. As used herein,“saccharide-initiated polyether polyol” refers to a polyether polyolprepared by reacting at least one alkylene oxide with one or moresuitable starter compounds in the presence of a suitable catalyst, inwhich the starter compounds comprise one or more saccharide initiators.Examples of suitable alkylene oxides include ethylene oxide, propyleneoxide, butylene oxide, styrene oxide, epichlorohydrin, or a mixture ofany two or more thereof. Some examples of suitable saccharide initiatorsare sucrose, sorbitol, maltitol, etc. as well as other mono-saccharides,di-saccharides, tri-saccharides and polysaccharides. Other initiatorcompounds are often used in combination with the saccharide initiator toprepare the saccharide initiated polyether polyol. Saccharides can beco-initiated with for example, compounds such as water, propyleneglycol, glycerin, ethylene glycol, ethanol amines, diethylene glycol, ora mixture of any two or more thereof. As will be appreciated, it ispossible to use a wide variety of individual initiator compounds incombination with one another in which the functionality of theindividual initiator compounds does not fall within the functionalitiesset forth herein, provided that the average functionality of the mixtureof initiator compounds satisfies the overall functionality rangedisclosed herein.

Some examples of suitable catalysts which can be used include basiccatalysts (such as sodium or potassium hydroxide or tertiary amines suchas methyl imidazole) and double metal cyanide (DMC) catalysts.

In some implementations, the saccharide, such as sucrose, is firstreacted with ethylene oxide and then propylene oxide. In some cases, theethylene oxide is used in an amount of 10 to 50%, such as from 20 to40%, by weight of the total alkylene oxide used and the propylene oxideis used in an amount of from 50 to 90%, such as 60 to 80%, by weight ofthe total alkylene oxide used. In some implementations, the total amountof alkylene oxide used is selected so that the product has an averagemolecular weight of 300 to 1600 Da, such as 440 to 1000 Da.

In some implementations, the saccharide initiated polyether polyol hasan OH number of from 200 to 600 mg KOH/g, such as 300 to 550 mg KOH/g,such as 400 to 500 mg KOH/g, or, in some cases, 450 to 500 mg KOH/g, anda functionality of 4 to 6, such as 5 to 6, 5.2 to 5.8, or 5.2 to 5.4.

In some implementations, the saccharide-initiated polyether polyol isutilized in an amount of 1 to 20% by weight, such as 5 to 15% by weight,or, in some cases, 8 to 12% by weight, based on the total weight of thepolyol blend. In some implementations, the saccharide-initiatedpolyether polyol is utilized in an amount of 1 to 10% by weight, such as5 to 10% by weight, or, in some cases, 4 to 8% by weight, based on thetotal weight of the isocyanate-reactive composition. In certainimplementations, the saccharide-initiated polyether polyol is present inan amount such that the ratio, by weight, of aromatic polyester polyolto saccharide-initiated polyether polyol in the polyol blend is at least2:1, such as 2.0:1.0 to 20.0:1.0, 5.0:1.0 to 15.0:1.0 or, in some cases,8.0:1.0 to 12.0:1.0. In some implementations, saccharide-initiatedpolyether polyol and amine-initiated, such as alkanolamine-initiated,polyether polyol are present in the polyol blend in a weight ratio of0.5:1 to 4:1, 1:1: to 4:1 or 1.5:1 to 2.5:1.

If desired, the polyol blend may include additional compounds thatcontain isocyanate-reactive groups, such as chain extenders and/orcrosslinking agents, and higher molecular weight polyether polyols andpolyester polyols not described above. Chain extenders and/orcrosslinking agents include, for example, ethylene glycol, propyleneglycol, butylene glycol, glycerol, diethylene glycol, dipropyleneglycol, dibutylene glycol, trimethylolpropane, pentaerythritol, ethylenediamine, diethyltoluenediamine, etc. Polyester polyols may be preparedfrom, for example, an organic dicarboxylic acid having 2 to 12 carbonatoms, such as an aliphatic dicarboxylic acid having 4 to 6 carbonatoms, and a polyvalent alcohol, such as a diol or triol having 2 to 12carbon atoms. Examples of the dicarboxylic acid are succinic acid,glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid,decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid,isophthalic acid and terephthalic acid. Instead of a free dicarboxylicacid, a corresponding dicarboxylic acid derivative such as adicarboxylic acid monoester or diester prepared by esterification withan alcohol having 1 to 4 carbon atoms or dicarboxylic anhydride can beused.

In certain implementations, the polyol blend has a weighted averagefunctionality of 2 to 4, such as 2 to 3 or 2.5 to 3.0, and/or a weightedaverage hydroxyl number of 300 to 500 mg KOH/g, such as 300 to 400 mgKOH/g.

In certain implementations, the polyol blend comprises less than 20% byweight, less than 10% by weight, less than 5% by weight, or, in somecases, less than 1% by weight, of ethylene oxide, based on the totalweight of polyether polyol that is present in the polyol blend.

As indicated earlier, the isocyanate-reactive compositions of thisspecification further comprises a blowing agent composition. The blowingagent composition comprises: (1) a physical blowing agent comprisingHCFO; and (2) a carbon dioxide generating chemical blowing agent.

Suitable HCFOs include 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd, Eand/or Z isomers), 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf),HCF01223, 1,2-dichloro-1,2-difluoroethene (E and/or Z isomers),3,3-dichloro-3-fluoropropene, 2-chloro-1,1,1,4,4,4-hexafluorobutene-2 (Eand/or Z isomers), 2-chloro-1,1,1,3,4,4,4-heptafluorobutene-2 (E and/orZ isomers). In some implementations, the boiling point, at atmosphericpressure, of the HCFO is at least −25° C., at least −20° C., or, in somecases, at least −19° C., and 40° C. or less, such as 35° C. or less, or,in some cases 33° C. or less. The HCFO may have a boiling point, atatmospheric pressure, of, for example, −25° C. to 40° C., or −20° C. to35° C., or −19° C. to 33° C.

In some implementations, the HCFO is utilized in an amount of at least10% by weight, such as 10 to 30% by weight or 10 to 20% by weight, basedon the total weight of the isocyanate-reactive composition.

In certain implementations, the isocyanate-reactive compositioncomprises one or more other physical blowing agents, such as otherhalogenated blowing agents, such as CFCs, HCFCs, and/or HFCs and/orhydrocarbon blowing agents, such as butane, n-pentane, cyclopentane,hexane, and/or isopentane (i.e. 2-methylbutane), etc. In otherembodiments, the isocyanate-reactive composition is substantially or, insome cases, completely free, of other physical blowing agents, such asother halogenated blowing agents, such as CFCs, HCFCs, and/or HFCsand/or hydrocarbon blowing agents, such as butane, n-pentane,cyclopentane, hexane, and/or isopentane (i.e. 2-methylbutane). As usedherein, the term “substantially free” when used with reference to theseblowing agents, means that the blowing agent is present, if at all, inan amount of less than 10% by weight, such as less than 1% by weight,based on the total weight of the blowing agent composition.

As indicated above, the isocyanate-reactive composition comprises acarbon dioxide generating chemical blowing agent, such as water and/orformate-blocked amines. In some of these implementations, the carbondioxide generating chemical blowing agent, such as water, is utilized inan amount of from 0.5 to 5.0% by weight, such as 1 to 4% by weight, or1.0 to 3.0% by weight, or 1.5 to 2.0% by weight, based on the totalweight of the isocyanate-reactive composition.

In certain implementations, the blowing agent composition comprises HCFOand a carbon dioxide generating chemical blowing agent, such as water,wherein the HCFO and the carbon dioxide generating chemical blowingagent are present in an amount of at least 90% by weight, such as atleast 95% by weight, or, in some cases, at least 99% by weight, based onthe total weight of the blowing agent composition. In certainimplementations, HCFO and carbon dioxide generating chemical blowingagent are present in the blowing agent composition at a weight ratio ofat least 2:1, such as at least 5:1, 5:1 to 15:1 or 8:1 to 12:1.

If desired, the blowing agent composition may include other physicalblowing agents, such as (a) other hydrofluoroolefins (HFOs), such aspentafluoropropane, tetrafluoropropene, 2,3,3,3-tetrafluoropropene,1,2,3,3-tetrafluoropropene, trifluoropropene, tetrafluorobutene,pentafluorobutene, hexafluorobutene, heptafluorobutene,heptafluoropentene, octafluoropentene, and nonafluoropentene; (b)hydrofluorocarbons (c) hydrocarbons, such as any of the pentane isomersand butane isomers; (d) hydrofluoroethers (HFEs); (e) C₁ to C₅ alcohols,C₁ to C₄ aldehydes, C₁ to C₄ ketones, C₁ to C₄ ethers and diethers andcarbon dioxide. Specific examples of such blowing agents are describedin United States Patent Application Publication No. US 2014/0371338 A1at [0051] and [0053], the cited portion of which being incorporatedherein by reference.

In some implementations, the isocyanate-reactive composition alsocomprises a surfactant. Any suitable surfactant can be used, includingorganosilicon compounds, such as polysiloxane-polyalkyene-blockcopolymers, such as a polyether-modified polysiloxane. Other usefulsurfactants include polyethylene glycol ethers of long chain alcohols,tertiary amine or alkanolamine salts of long chain alkyl acid sulfateesters, alkylsulfonic esters, or alkylarylsulfonic acids. Suchsurfactants are employed in amounts sufficient to stabilize the foamingreaction mixture against collapse and the formation of large and unevencells. In some implementations, surfactant is utilized in an amount of0.2 to 5.0% by weight, such as 1 to 3% by weight, based on the totalweight of the isocyanate-reactive composition.

As indicated earlier, the isocyanate-reactive composition furthercomprises a tertiary amine catalyst. As will be appreciated, tertiaryamine catalysts are known as “blow catalysts” since they have a greatereffect on the water-polyisocyanate blowing reaction. In someimplementations, tertiary amine catalyst comprises a morpholine and/oran imidazole. Suitable morpholine catalysts include, for example,dimorpholinodiethylether, dimorpholinodimethylether, N-ethylmorpholine,and N-methylmorpholine. Suitable imidazole catalysts include, forexample, imidazole, n-methylimidazole, and 1,2-dimethylimidazole.

In some implementations of the isocyanate-reactive compositions of thisspecification, however, the tertiary amine catalyst can be used in arelatively low amounts while still achieve the desired level ofreactivity of the water-polyisocyanate blowing reaction. For example, insome implementations, the tertiary amine catalyst, such as themorpholine and/or imidazole, is present in an amount of less than 2% byweight, such as 0.1 to 1.9% by weight, or 0.5 to 1.5% by weight based onthe total weight of the isocyanate-reactive composition. In someimplementations, the isocyanate-reactive composition comprises atertiary amine catalyst composition comprising: (1) 80 to 99% by weight,based on the total weight of the tertiary amine catalyst composition, ofa morpholine; and (2) 1 to 20% by weight, based on the total weight ofthe tertiary amine catalyst composition, of an imidazole.

Moreover, in some implementations, the isocyanate-reactive compositioncan be substantially or, in some cases, completely free of gel catalyst,such as organometallic catalysts (for example dibutyltin dilaurate,dibutyltin diacetate, stannous octoate, potassium octoate, potassiumacetate, and potassium lactate) that catalyze the reaction between apolyol and a polyisocyanate. As used herein, the term “substantiallyfree”, when used with reference to the absence of a catalyst, means thatthe catalyst is present in an amount of no more than 0.1% by weight,based on the total weight of the isocyanate-reactive composition.

In certain implementations, the isocyanate-reactive composition furthercomprises a trimerization catalyst, which is not an amine catalyst. Aswill be appreciated, a trimerization catalyst is a material thatcatalyzes the formation of isocyanurate groups from polyisocyanates.This means that isocyanates can react with one another to formmacromolecules with isocyanurate structures (polyisocyanurates). Thereactions between isocyanates and polyols to form urethanes andisocyanates and isocyanates (homopolymerization) to form isocyanuratescan occur at the same time or one after the other to form macromoleculeswith urethanes and isocyanurates.

Various trimerization catalysts may be suitable. In someimplementations, however, the trimerization catalyst comprises aquaternary ammonium salt, such as a quaternary ammonium carboxylate.Useful quaternary ammonium carboxylates include, for example,(2-hydroxypropyl)trimethylammonium 2-ethylhexanoate (Dabco® TMR fromEvonik Industries) and (2-hydroxypropyl)trimethylammonium formate(Dabco® TMR-2 from Evonik Industries). In some implementations, thetrimerization catalyst is present in the isocyanate-reactive compositionin an amount of from 0.25 to 3.0% by weight, such as 0.25 to 1% byweight, based on the total weight of the isocyanate-reactivecomposition.

Additional materials which may optionally be included in thefoam-forming compositions include: pigments, colorants, fillers,antioxidants, flame retardants, and stabilizers. Exemplary flameretardants useful in the foam-forming compositions include, but are notlimited to, reactive bromine based compounds known to be used inpolyurethane chemistry and chlorinated phosphate esters, including butnot limited to, tetrabromophthalate diol (theoretical formulaC₁₅H₁₆O₇Br₄), tri(2-chloroethyl)phosphate (TECP),tri(1,3-dichloro-2-propyl)phosphate, tri(1-chloro-2-propyl)phosphate(TCPP) and dimethyl propyl phosphate (DMPP).

This specification is also directed to processes for producing rigidpolyurethane-polyisocyanurate (“PUR-PIR”) foams. In such processes, apolyisocyanate is reacted with an isocyanate-reactive composition of thetype described above. In some implementations, the isocyanate functionalcomponent and the isocyanate-reactive composition are mixed at anisocyanate index of from 90 to 150, such as 120 to 150.

In certain implementations, the polyol blend of the isocyanate-reactivecomposition is reacted with a polyisocyanate in the presence of theblowing agent composition, the catalyst composition, a surfactant andany other optional ingredients. The rigid foams may be prepared byblending all of the components of the isocyanate reactive compositiontogether in a phase stable mixture, and then mixing this in the properratio with the polyisocyanate. Alternatively, one or more of thecomponents, such as the surfactant, may be combined with thepolyisocyanate prior to mixing it with the isocyanate reactivecomponent. Other possible implementations would include adding one ormore of the components as a separate stream, together with theisocyanate reactive component and polyisocyanate. As used herein, theterm phase stable means that the isocyanate-reactive composition willnot separate when stored for 7 days at about 70° F. (or 21° C.).

Many foam machines are designed to condition and mix only two componentsin the proper ratio. For use of these machines, a premix of all thecomponents except the polyisocyanate can be advantageously employed.According to the two-component method (component A: polyisocyanate; andcomponent B: isocyanate-reactive composition which typically includesthe polyol blend, blowing agent, water, catalyst and surfactant), thecomponents may be mixed in the proper ratio at a temperature of 5 to 50°C., such as 15 to 35° C., injected or poured into a mold having thetemperature controlled to within a range of from 20 to 70° C., such as35 to 60° C. The mixture then expands to fill the cavity with the rigidpolyurethane foam. This simplifies the metering and mixing of thereacting components which form the foam-forming mixture, but requiresthat the isocyanate-reactive composition be phase stable.

Alternatively, the rigid polyurethane foams may also be prepared by theso-called “quasi prepolymer” method. In this method, a portion of thepolyol component is reacted in the absence of the urethane-formingcatalysts with the polyisocyanate component in proportion so as toprovide from 10 percent to 35 percent of free isocyanate groups in thereaction product based on the prepolymer. To prepare foam, the remainingportion of the polyol is added and the components are allowed to reacttogether in the presence of the blowing agent and other appropriateadditives such as the catalysts, and surfactants. Other additives may beadded to either the isocyanate prepolymer or remaining polyol or bothprior to the mixing of the components, whereby at the end of thereaction, rigid foam is provided.

Furthermore, the rigid foam can be prepared in a batch or continuousprocess by the one-shot or quasi-prepolymer methods using any well-knownfoaming apparatus. The rigid foam may be produced in the form of slabstock, moldings, cavity fillings, sprayed foam, frothed foam orlaminates with other materials such as hardboard, plasterboard,plastics, paper or metal as facer substrates.

For closed-cell insulating foams, the object is to retain the blowingagent in the cells to maintain a low thermal conductivity of theinsulating material, i.e., the rigid foam. Thus, high closed-cellcontent in the foam is desirable. Foams produced according toimplementations of the present specification have more than 80 percent,typically more than 85 percent, or more than 88 percent closed-cellcontent as measured according to ASTM D6226-15.

This specification also relates to the use of the rigid foams describedherein for thermal insulation. That is, the rigid foams of the presentspecification may find use as an insulating material in refrigerationapparatuses since the combination of good thermal insulation and otherproperties described herein is particularly appropriate here. The rigidfoams can be used, for example, as an intermediate layer in compositeelements or for filling hollow spaces of refrigerators and freezers, orrefrigerated trailers. The foams may also find use in the constructionindustry or for thermal insulation of long-distance heating pipes andcontainers.

As such, this specification also provides a composite article comprisingrigid foam as disclosed herein sandwiched between one or more facersubstrates. In certain implementations, the facer substrate may beplastic (such a polypropylene resin reinforced with continuousbi-directional glass fibers or a fiberglass reinforced polyestercopolymer), paper, wood, or metal. For example, in certainimplementations, the composite article may be a refrigeration apparatussuch as a refrigerator, freezer, or cooler with an exterior metal shelland interior plastic liner. In certain implementations, therefrigeration apparatus may be a trailer, and the composite article mayinclude the foams produced according to this specification in sandwichcomposites for trailer floors.

It has been found, surprisingly, that the particular isocyanate-reactivecompositions described herein can be particularly suitable for use indiscontinuous open pour applications, such as is often used in theproduction of discontinuous panels or doors, such as garage doors. Aswill be appreciated, in such a discontinuous process, the reactionmixture (the mixture of the isocyanate-reactive component and theisocyanate-functional component) is poured into a cavity of a mold ofthe desired part, in which the cavity is lined with a facer, which canbe a metal sheet, particle board, plaster board, fiber cement, or aplastic. The foam adheres to the facers as it reacts and cures. Theresulting faced panel is then removed from the cavity. To be effectivelyused in such a process, the reaction mixture must exhibit the rightlevel of reactivity (sufficient to allow for adequate flow of themixture) resulting from an ideal balance of blow and gel reactivity. Asa result, certain implementations of this specification are directed tothe use of the reaction mixtures described herein in such a process.

It was discovered, surprisingly, that certain isocyanate-reactivecompositions described herein, while having a long shelf life, canproduce flame retardant rigid PUR-PIR foams having a good combination ofphysical properties, even while limiting the amount of tertiary amineblow catalyst used. First, in some implementations, the rigid foams canachieve a Class A fire rating according to ASTM E84-21. Second, therigid foams can exhibit a thermal conductivity measured at 23° F. (−5°C.) of less than 0.125 BTU-in/h-ft²-° F. as measured according to ASTMC518-15 at a core foam density of 2.0 to 2.2 lb/ft³ (32.0 to 35.2kg/m³). Third, the isocyanate-reactive composition is phase stable andhas a long shelf life. Here, when it is stated that theisocyanate-reactive composition has a “long” shelf life it means thatafter storing the isocyanate-reactive composition for 6 days (144 hours)at 60° C., when the isocyanate-reactive composition is combined with thepolyisocyanate, both (a) the cream and gel times of the foam producedthereby remains within 10% of the initial cream and gel times (the creamand gel times of such a foam if produced immediately and not afterstoring the isocyanate-reactive composition for 6 days (144 hours) at60° C.) and (b) the free rise density of the foam produced therebyremains within 10% of the initial free rise density (the free risedensity of such a foam is produced immediately and not after storing theisocyanate-reaction composition for 6 days (144 hours) at 60° C.) evenin cases where the isocyanate-reactive composition comprises 15 to 20%by weight HCFO, based on the total weight of the isocyanate-reactivecomposition.

Various aspects of the subject matter described herein are set out inthe following numbered clauses:

Clause 1. An isocyanate-reactive composition comprising: (a) a polyolblend comprising: (1) aromatic polyester polyol (I) having afunctionality of 1.5 to less than 2.5 and an OH number of 150 to 360 mgKOH/g; (2) an aromatic polyester polyol (II) having a functionality ofat least 2.5 and an OH number greater than 360 mg KOH/g, which ispresent in an amount of at least 10% by weight, based on the totalweight of the aromatic polyester polyol in the polyol blend; and (3) anamine-initiated, such as an alkanolamine-initiated, polyether polyolhaving an OH number of at least 500 mg KOH/g and a functionality of 2.5to 4, wherein aromatic polyester polyol is present in an amount of atleast 50% by weight, based on the total weight of the polyol blend; (b)a blowing agent composition comprising: (1) a hydrochlorofluoroolefinand a carbon dioxide generating chemical blowing agent; and (c) atertiary amine catalyst.

Clause 2. The isocyanate-reactive composition of clause 1, whereinaromatic polyester polyol (1) has an OH number of 200 to 335 mg KOH/g or200 to 250 mg KOH/g, and a functionality of 1.8 to less than 2.5, 1.8 to2.2 or 1.9 to 2.1.

Clause 3. The isocyanate-reactive composition of clause 1 or clause 2,wherein aromatic polyester polyol (2) has an OH number of no more than500 mg KOH/g, no more than 400 mg KOH/g, or 365 to 385 mg KOH/g, and afunctionality of 2.5 to 3.5, 2.8 to 3.2, 2.9 to 3.1, or 3.0.

Clause 4. The isocyanate-reactive composition of one of clause 1 toclause 3, wherein aromatic polyester polyol is present in an amount of50 to 85% by weight, 50 to 70% by weight, 55 to 65% by weight, or 55 to60% by weight, based on the total weight of the isocyanate-reactivecomposition.

Clause 5. The isocyanate-reactive composition of one of clause 1 toclause 4, wherein aromatic polyester polyol present in an amount of 50to 95% by weight, 70 to 90% by weight, or 80 to 90% by weight, based ontotal weight of polyol blend that is in the isocyanate-reactivecomposition.

Clause 6. The isocyanate-reactive composition of one of clause 1 toclause 5, wherein aromatic polyester polyol (1) and aromatic polyesterpolyol (2) are present in a relative ratio, by weight, of 0.5:1.0 to2.0:1.0, 0.5:1.0 to 1.5:1.0, 0.8:1.0 to 1.2:1.0, or 1.0:1.0 to 1.2:1.0.

Clause 7. The isocyanate-reactive composition of one of clause 1 toclause 6, wherein the amine-initiated polyether polyol an OH number of500 to 900 mg KOH/g, 600 to 800 mg KOH/g, or 680 to 720 mg KOH/g, and afunctionality of 2.5 to 4 or 2.5 to 3.5.

Clause 8. The isocyanate-reactive composition of one of clause 1 toclause 7, wherein the amine-initiated polyether polyol is present in anamount of 0.1 to 10%, 1 to 10% by weight or 2 to 6% by weight, basedupon the total weight of the polyol blend that is in theisocyanate-reactive composition.

Clause 9. The isocyanate-reactive composition of one of clause 1 toclause 8, wherein the amine-initiated polyether polyol is present in anamount of 0.1 to 10% by weight, 0.1 to 5% by weight, or 1 to 5% byweight, based on the total weight of the isocyanate-reactivecomposition.

Clause 10. The isocyanate-reactive composition of one of clause 1 toclause 9, wherein the aromatic polyester polyol and the amine-initiatedpolyether polyol are present in a weight ratio of at least 10:1, 10:1 to50:1, 10:1 to 30:1 or 15:1 to 25:1.

Clause 11. The isocyanate-reactive composition of one of clause 1 toclause 10, wherein the polyol blend further comprises asaccharide-initiated polyether polyol.

Clause 12. The isocyanate-reactive composition of clause 11, wherein thesaccharide initiated polyether polyol has an OH number of 200 to 600 mgKOH/g, 300 to 550 mg KOH/g, 400 to 500 mg KOH/g, or 450 to 500 mg KOH/g,and a functionality of 4 to 6, 5 to 6, 5.2 to 5.8, or 5.2 to 5.4.

Clause 13. The isocyanate-reactive composition of clause 11 or clause12, wherein the saccharide-initiated polyether polyol is present in anamount of 1 to 20% by weight, 5 to 15% by weight, or 8 to 12% by weight,based on the total weight of the polyol blend that is in theisocyanate-reactive composition.

Clause 14. The isocyanate-reactive composition of one of clause 11 toclause 13, wherein the saccharide-initiated polyether polyol is presentin an amount of 1 to 10% by weight, 5 to 10% by weight, or 4 to 8% byweight, based on the total weight of the isocyanate-reactivecomposition.

Clause 15. The isocyanate-reactive composition of one of clause 11 toclause 14, wherein the saccharide-initiated polyether polyol is presentin an amount such that the ratio, by weight, of aromatic polyesterpolyol to saccharide-initiated polyether polyol is at least 2:1, 2.0:1.0to 20.0:1.0, 5.0:1.0 to 15.0:1.0 or 8.0:1.0 to 12.0:1.0.

Clause 16. The isocyanate-reactive composition of one of clause 11 toclause 15, wherein the saccharide-initiated polyether polyol and theamine-initiated polyether polyol are present in a weight ratio of 0.5:1to 4:1, 1:1 to 4:1 or 1.5:1 to 2.5:1.

Clause 17. The isocyanate-reactive composition of one of clause 1 toclause 16 wherein the polyol blend has a weighted average functionalityof 2 to 4, 2 to 3 or 2.5 to 3.0, and/or a weighted average hydroxylnumber of from 300 to 500 mg KOH/g or 300 to 400 mg KOH/g.

Clause 18. The isocyanate-reactive composition of one of clause 1 toclause 17, wherein the polyol blend comprises less than 20% by weight,less than 10% by weight, less than 5% by weight, or less than 1% byweight, of ethylene oxide, based on the total weight of polyether polyolthat is present in the polyol blend.

Clause 19. The isocyanate-reactive composition of one of clause 1 toclause 18, wherein the hydrochlorofluoroolefin comprises1-chloro-3,3,3-trifluoropropene (HCFO-1233zd, E and/or Z isomers),2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), HCF01223,1,2-dichloro-1,2-difluoroethene (E and/or Z isomers),3,3-dichloro-3-fluoropropene, 2-chloro-1,1,1,4,4,4-hexafluorobutene-2 (Eand/or Z isomers), or 2-chloro-1,1,1,3,4,4,4-heptafluorobutene-2 (Eand/or Z isomers).

Clause 20. The isocyanate-reactive composition of one of clause 1 toclause 19, wherein the hydrochlorofluoroolefin has a boiling point, atatmospheric pressure, of at least −25° C., at least −20° C., or at least−19° C., and 40° C. or less, 35° C. or less, or 33° C. or less, such aswhere the hydrochlorofluoroolefin has a boiling point, at atmosphericpressure, of −25° C. to 40° C., −20° C. to 35° C., or −19° C. to 33° C.

Clause 21. The isocyanate-reactive composition of one of clause 1 toclause 20, wherein the hydrochlorofluoroolefin is present in an amountof at least 10% by weight, 10 to 30% by weight or 10 to 20% by weight,based on the total weight of the isocyanate-reactive composition.

Clause 22. The isocyanate-reactive composition of one of clause 1 toclause 21, wherein the isocyanate-reactive composition substantially, orcompletely free, of other physical blowing agents, such as otherhalogenated blowing agents, such as CFCs, HCFCs, and/or HFCs and/orhydrocarbon blowing agents, such as butane, n-pentane, cyclopentane,hexane, and/or isopentane (i.e. 2-methylbutane).

Clause 23. The isocyanate-reactive composition of one of clause 1 toclause 22, wherein the carbon dioxide generating chemical blowing agentcomprises water, such as where water is present in an amount of from 0.5to 5.0% by weight, 1 to 4% by weight, 1.0 to 3.0% by weight, or 1.5 to2.0% by weight, based on the total weight of the isocyanate-reactivecomposition.

Clause 24. The isocyanate-reactive composition of one of clause 1 toclause 24, wherein the hydrochlorofluoroolefin and carbon dioxidegenerating chemical blowing agent are present in an amount of at least90% by weight, at least 95% by weight, or at least 99% by weight, basedon the total weight of the blowing agent composition.

Clause 25. The isocyanate-reactive composition of one of clause 1 toclause 24, wherein the hydrochlorofluoroolefin and carbon dioxidegenerating chemical blowing agent are present in the blowing agentcomposition at a weight ratio of at least 2:1, at least 5:1, 5:1 to 15:1or 8:1 to 12:1.

Clause 26. The isocyanate-reactive composition of one of clause 1 toclause 25, wherein the tertiary amine catalyst comprises a morpholineand/or an imidazole, such as where the morpholine comprisesdimorpholinodiethylether, dimorpholinodimethylether, N-ethylmorpholine,or N-methylmorpholine and/or the imidazole comprises imidazole,n-methylimidazole, or 1,2-dimethylimidazole.

Clause 27. The isocyanate-reactive composition of one of clause 1 toclause 26, wherein the tertiary amine catalyst is present in an amountof less than 2% by weight, such as 0.1 to 1.9% by weight, or 0.5 to 1.5%by weight based on the total weight of the isocyanate-reactivecomposition.

Clause 28. The isocyanate-reactive composition of one of clause 1 toclause 27, wherein the tertiary amine catalyst composition comprises:(1) 80 to 99% by weight, based on the total weight of the tertiary aminecatalyst composition, of a morpholine; and (2) 1 to 20% by weight, basedon the total weight of the tertiary amine catalyst composition, of animidazole.

Clause 29. The isocyanate-reactive composition of one of clause 1 toclause 28, wherein the isocyanate-reactive composition is substantiallyor completely free of organometallic gel catalysts (for exampledibutyltin dilaurate, dibutyltin diacetate, stannous octoate, potassiumoctoate, potassium acetate, and potassium lactate).

Clause 30. The isocyanate-reactive composition of one of clause 1 toclause 29, wherein the isocyanate-reactive composition further comprisesa trimerization catalyst, such as a quaternary ammonium salt, such as aquaternary ammonium carboxylate, such as(2-hydroxypropyl)trimethylammonium 2-ethylhexanoate and(2-hydroxypropyl)trimethylammonium formate, such as where thetrimerization catalyst is present in an amount of from 0.25 to 3.0% byweight or 0.25 to 1% by weight, based on the total weight of theisocyanate-reactive composition.

Clause 31. The isocyanate-reactive composition of one of clause 1 toclause 30, further comprising a reactive bromine based compound and/or achlorinated phosphate esters, such as tetrabromophthalate diol,tri(2-chloroethyl)phosphate (TECP), tri(1,3-dichloro-2-propyl)phosphate,tri(1-chloro-2-propyl)phosphate (TCPP) or dimethyl propyl phosphate(DMPP).

Clause 32. A polyurethane foam-forming reaction mixture comprising theisocyanate-reactive composition of one of clause 1 to clause 31 and apolyisocyanate, such as where the polyisocyanate comprises m-phenylenediisocyanate, p-phenylene diisocyanate, 2,4-toluene diisocyanate,2,6-toluene diisocyanate, 1,6-hexamethylene diisocyanate,1,4-hexamethylene diisocyanate, 1,3-cyclohexane diisocyanate,1,4-cyclo-hexane diisocyanate, an isomer of hexahydro-toluenediisocyanate, isophorone diisocyanate, a dicyclo-hexylmethanediisocyanate, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethanediisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-biphenylenediisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate and3,3′-dimethyl-diphenyl-propane-4,4′-diisocyanate; triisocyanates such as2,4,6-toluene triisocyanate;4,4′-dimethyl-diphenylmethane-2,2′,5,5′-tetraisocyanate or thepolymethylene polyphenyl-polyisocyanates.

Clause 33. The polyurethane foam-forming composition of clause 32,wherein the polyisocyanate comprises a methylene-bridged polyphenylpolyisocyanate and/or a prepolymer of methylene-bridged polyphenylpolyisocyanates having an average functionality of 1.8 to 3.5 or 2.0 to3.1, isocyanate moieties per molecule, and an NCO content of 25 to 32weight percent.

Clause 34. A method of forming a foam, comprising mixing apolyisocyanate with the isocyanate-reactive composition of one of clause1 to clause 31 at an isocyanate index of from 90 to 150, such as 120 to150.

Clause 35. The method of clause 34, wherein the mixture is poured into acavity of a mold of a desired part, in which the cavity is lined with afacer, such as a metal sheet, particle board, plaster board, fibercement, or a plastic, the foam adheres to the facers as it reacts andcures, and the resulting faced panel is then removed from the cavity.

Clause 36. A foam produced by the method of clause 34 or clause 35.

Clause 37. A composite article comprising the foam of clause 36sandwiched between one or more facer substrates, such as where the facersubstrate comprises plastic, such a polypropylene resin reinforced withcontinuous bi-directional glass fibers or a fiberglass reinforcedpolyester copolymer, paper, wood, or metal.

Clause 38. The foam of clause 36 or the composite article of clause 37,wherein the foam achieves an ASTM E-84 Class A fire rating.

Clause 39. The foam of clause 36 or the composite article of clause 38,wherein the foam exhibits a thermal conductivity measured at 23° F. (−5°C.) of less than 0.125 BTU-in/h-ft2-° F. as measured according to ASTMC518-15 at a core foam density of 2.0 to 2.2 lb/ft3 (32.0 to 35.2kg/m3).

Clause 40. A foam-forming reaction mixture comprising: (a) apolyisocyanate; (b) a polyol blend comprising: (1) an aromatic polyesterpolyol (I) having a functionality of 1.5 to less than 2.5 and an OHnumber of 150 to 360 mg KOH/g; (2) an aromatic polyester polyol (II)having a functionality of at least 2.5 and an OH number greater than 360mg KOH/g, which is present in an amount of at least 10% by weight, basedon the total weight of the aromatic polyester polyol in the polyolblend; and (3) an amine-initiated, such as an alkanolamine-initiated,polyether polyol having an OH number of at least 500 mg KOH/g and afunctionality of 2.5 to 4, wherein aromatic polyester polyol is presentin an amount of at least 50% by weight, based on the total weight of thepolyol blend; (c) a blowing agent composition comprising: (1) ahydrochlorofluoroolefin and a carbon dioxide generating chemical blowingagent; and (d) a tertiary amine catalyst, wherein the reaction mixturehas an isocyanate index of 90 to 150, such as 120 to 150.

Clause 41. The foam-forming reaction mixture of clause 40, whereinaromatic polyester polyol (I) has an OH number of 200 to 335 mg KOH/g or200 to 250 mg KOH/g, and a functionality of 1.8 to less than 2.5, 1.8 to2.2 or 1.9 to 2.1.

Clause 42. The foam-forming reaction mixture of clause 40 or clause 41,wherein aromatic polyester polyol (II) has an OH number of no more than500 mg KOH/g, no more than 400 mg KOH/g, or 365 to 385 mg KOH/g, and afunctionality of 2.5 to 3.5, 2.8 to 3.2, 2.9 to 3.1, or 3.0.

Clause 43. The foam-forming reaction mixture of one of clause 40 toclause 42, wherein aromatic polyester polyol present in an amount of 50to 95% by weight, 70 to 90% by weight, or 80 to 90% by weight, based ontotal weight of the polyol blend.

Clause 44. The foam-forming reaction mixture of one of clause 40 toclause 43, wherein aromatic polyester polyol (I) and aromatic polyesterpolyol (II) are present in a relative ratio, by weight, of 0.5:1.0 to2.0:1.0, 0.5:1.0 to 1.5:1.0, 0.8:1.0 to 1.2:1.0, or 1.0:1.0 to 1.2:1.0.

Clause 45. The foam-forming reaction mixture of one of clause 40 toclause 44, wherein the amine-initiated polyether polyol has an OH numberof 500 to 900 mg KOH/g, 600 to 800 mg KOH/g, or 680 to 720 mg KOH/g, anda functionality of 2.5 to 4 or 2.5 to 3.5.

Clause 46. The foam-forming reaction mixture of one of clause 40 toclause 45, wherein the amine-initiated polyether polyol is present in anamount of 0.1 to 10%, 1 to 10% by weight or 2 to 6% by weight, basedupon the total weight of the polyol blend.

Clause 47. The foam-forming reaction mixture of one of clause 40 toclause 46, wherein aromatic polyester polyol and amine-initiatedpolyether polyol are present in a weight ratio of at least 10:1, 10:1 to50:1, 10:1 to 30:1 or 15:1 to 25:1.

Clause 48. The foam-forming reaction mixture of one of clause 40 toclause 47, wherein the polyol blend further comprises asaccharide-initiated polyether polyol having an OH number of 200 to 600mg KOH/g, 300 to 550 mg KOH/g, 400 to 500 mg KOH/g, or 450 to 500 mgKOH/g, and a functionality of 4 to 6, 5 to 6, 5.2 to 5.8, or 5.2 to 5.4.

Clause 49. The foam-forming reaction mixture of clause 48, wherein thesaccharide-initiated polyether polyol is present in an amount of 1 to20% by weight, 5 to 15% by weight, or 8 to 12% by weight, based on thetotal weight of the polyol blend.

Clause 50. The foam-forming reaction mixture of clause 48 or clause 49,wherein the saccharide-initiated polyether polyol is present in anamount such that the ratio, by weight, of aromatic polyester polyol tosaccharide-initiated polyether polyol is at least 2:1, 2.0:1.0 to20.0:1.0, 5.0:1.0 to 15.0:1.0 or 8.0:1.0 to 12.0:1.0.

Clause 51. The foam-forming reaction mixture of one of clause 48 toclause 50, wherein saccharide-initiated polyether polyol andamine-initiated polyether polyol are present in a weight ratio of 0.5:1to 4:1, 1:1: to 4:1 or 1.5:1 to 2.5:1.

Clause 52. The foam-forming reaction mixture of one of clause 40 toclause 51 wherein the polyol blend has a weighted average functionalityof 2 to 4, 2 to 3 or 2.5 to 3.0, and/or a weighted average hydroxylnumber of from 300 to 500 mg KOH/g or 300 to 400 mg KOH/g.

Clause 53. The foam-forming reaction mixture of one of clause 40 toclause 52, wherein the polyol blend comprises less than 20% by weight,less than 10% by weight, less than 5% by weight, or less than 1% byweight, of ethylene oxide, based on the total weight of polyether polyolthat is present in the polyol blend.

Clause 54. The foam-forming reaction mixture of one of clause 40 toclause 53, wherein the hydrochlorofluoroolefin comprises1-chloro-3,3,3-trifluoropropene (HCFO-1233zd, E and/or Z isomers),2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), HCF01223,1,2-dichloro-1,2-difluoroethene (E and/or Z isomers),3,3-dichloro-3-fluoropropene, 2-chloro-1,1,1,4,4,4-hexafluorobutene-2 (Eand/or Z isomers), or 2-chloro-1,1,1,3,4,4,4-heptafluorobutene-2 (Eand/or Z isomers).

Clause 55. The foam-forming reaction mixture of one of clause 40 toclause 54, wherein the hydrochlorofluoroolefin has a boiling point, atatmospheric pressure, of at least −25° C., at least −20° C., or at least−19° C., and 40° C. or less, 35° C. or less, or 33° C. or less, such aswhere the hydrochlorofluoroolefin has a boiling point, at atmosphericpressure, of −25° C. to 40° C., −20° C. to 35° C., or −19° C. to 33° C.

Clause 56. The foam-forming reaction mixture of one of clause 40 toclause 55, wherein the hydrochlorofluoroolefin is present in an amountof at least 10% by weight, 10 to 30% by weight or 10 to 20% by weight,based on the total weight of the foam-forming reaction mixture exceptfor the weight of the polyisocyanate.

Clause 57. The foam-forming reaction mixture of one of clause 40 toclause 56, wherein the foam-forming reaction mixture is substantially,or completely free, of other physical blowing agents, such as otherhalogenated blowing agents, such as CFCs, HCFCs, and/or HFCs and/orhydrocarbon blowing agents, such as butane, n-pentane, cyclopentane,hexane, and/or isopentane (i.e. 2-methylbutane).

Clause 58. The foam-forming reaction mixture of one of clause 40 toclause 57, wherein the carbon dioxide generating chemical blowing agentcomprises water, such as where water is present in an amount of from 0.5to 5.0% by weight, 1 to 4% by weight, 1.0 to 3.0% by weight, or 1.5 to2.0% by weight, based on the total weight of the foam-forming reactionmixture except for the weight of the polyisocyanate.

Clause 59. The foam-forming reaction mixture of one of clause 40 toclause 58, wherein the hydrochlorofluoroolefin and carbon dioxidegenerating chemical blowing agent are present in an amount of at least90% by weight, at least 95% by weight, or at least 99% by weight, basedon the total weight of the blowing agent composition.

Clause 60. The foam-forming reaction mixture of one of clause 40 toclause 59, wherein the hydrochlorofluoroolefin and carbon dioxidegenerating chemical blowing agent are present in the blowing agentcomposition at a weight ratio of at least 2:1, at least 5:1, 5:1 to 15:1or 8:1 to 12:1.

Clause 61. The foam-forming reaction mixture of one of clause 40 toclause 60, wherein the tertiary amine catalyst comprises a morpholineand/or an imidazole, such as where the morpholine comprisesdimorpholinodiethylether, dimorpholinodimethylether, N-ethylmorpholine,or N-methylmorpholine and/or the imidazole comprises imidazole,n-methylimidazole, or 1,2-dimethylimidazole.

Clause 62. The foam-forming reaction mixture of one of clause 40 toclause 61, wherein the tertiary amine catalyst is present in an amountof less than 2% by weight, such as 0.1 to 1.9% by weight, or 0.5 to 1.5%by weight based on the total weight of the foam-forming reaction mixtureexcept for the weight of the polyisocyanate.

Clause 63. The foam-forming reaction mixture of one of clause 40 toclause 62, wherein the tertiary amine catalyst composition comprises:(1) 80 to 99% by weight, based on the total weight of the tertiary aminecatalyst composition, of a morpholine; and (2) 1 to 20% by weight, basedon the total weight of the tertiary amine catalyst composition, of animidazole.

Clause 64. The foam-forming reaction mixture of one of clause 40 toclause 63, wherein the foam-forming reaction mixture is substantially orcompletely free of organometallic gel catalysts (for example dibutyltindilaurate, dibutyltin diacetate, stannous octoate, potassium octoate,potassium acetate, and potassium lactate).

Clause 65. The foam-forming reaction mixture of one of clause 40 toclause 64, further comprising a trimerization catalyst, such as aquaternary ammonium salt, such as a quaternary ammonium carboxylate,such as (2-hydroxypropyl)trimethylammonium 2-ethylhexanoate and(2-hydroxypropyl)trimethylammonium formate, such as where thetrimerization catalyst is present in an amount of from 0.25 to 3.0% byweight or 0.25 to 1% by weight, based on the total weight of thefoam-forming reaction mixture except for the weight of thepolyisocyanate.

Clause 66. The foam-forming reaction mixture of one of clause 40 toclause 65, further comprising a reactive bromine based compound and/or achlorinated phosphate esters, such as tetrabromophthalate diol,tri(2-chloroethyl)phosphate (TECP), tri(1,3-dichloro-2-propyl)phosphate,tri(1-chloro-2-propyl)phosphate (TCPP) or dimethyl propyl phosphate(DMPP).

Clause 67. The foam-forming reaction mixture of one of clause 40 toclause 66, wherein the polyisocyanate comprises a methylene-bridgedpolyphenyl polyisocyanate and/or a prepolymer of methylene-bridgedpolyphenyl polyisocyanates having an average functionality of 1.8 to 3.5or 2.0 to 3.1, isocyanate moieties per molecule, and an NCO content of25 to 32 weight percent.

Clause 68. A foam comprising the reaction product of the foam-formingreaction mixture of one of clause 40 to clause 67.

Clause 69. A method of forming a foam, comprising pouring thefoam-forming reaction mixture of one of clause 40 to clause 67 into acavity of a mold of a desired part, in which the cavity is lined with afacer, such as a metal sheet, particle board, plaster board, fibercement, or a plastic, the foam adheres to the facers as it reacts andcures, and the resulting faced panel is then removed from the cavity.

Clause 70. A composite article comprising the foam of clause 68 orproduced by the method of clause 69, wherein the foam is sandwichedbetween one or more facer substrates, such as where the facer substratecomprises plastic, such a polypropylene resin reinforced with continuousbi-directional glass fibers or a fiberglass reinforced polyestercopolymer, paper, wood, or metal.

Clause 71. The foam of clause 68 or the composite article of clause 70,wherein the foam achieves an ASTM E-84 Class A fire rating.

Clause 72. The foam of clause 68 or the composite article of clause 71,wherein the foam exhibits a thermal conductivity measured at 23° F. (−5°C.) of less than 0.125 BTU-in/h-ft²-° F. as measured according to ASTMC518-15 at a core foam density of 2.0 to 2.2 lb/ft³ (32.0 to 35.2kg/m³).

The non-limiting and non-exhaustive examples that follow are intended tofurther describe various non-limiting and non-exhaustive implementationswithout restricting the scope of the implementations described in thisspecification.

Examples

Foam-forming compositions were prepared using the ingredients andamounts (in parts by weight) set forth in Table 1. The followingmaterials were used:

POLYOL 0: an aromatic polyester polyol having an OH number of 240 mgKOH/g and a functionality of 2. Commercially available from Stepan asStepanpol® PS-2352;

POLYOL 1: an aromatic polyester polyol having an OH number of 225 to 245mg KOH/g and a functionality of 2, commercially available from Invistaas Terate® HT-5500;

POLYOL 2: a sucrose and propylene glycol initiated polyether polyol(100% propylene oxide as the alkylene oxide) having an OH number of450-490 mg KOH/g and a functionality of 5.2;

POLYOL 3: a monoethanolamine-initiated polyether polyol having an OHnumber of 685 to 715, a functionality of 3, and a nitrogen content of5.8% by weight, prepared by propoxylating monoethanolamine;

POLYOL 4: a saturated aromatic terephthalate polyester polyol having anOH number of about 375 mg KOH/g and a functionality of about 3,commercially available from Coim as Isoexter® TB-375;

SURFACTANT 1: a non-hydrolysable polyether polydimethylsiloxanecopolymer commercially available from Evonik under the trade nameTegostab® B8465;

SURFACTANT 2: a non-hydrolysable polyether polydimethylsiloxanecopolymer commercially available from Evonik under the trade nameTegostab® B84725;

CATALYST 1: 2,2′-dimorpholinodiethylether (JEFFCAT® DMDEE fromHuntsman);

CATALYST 2: (2-hydroxypropyl)trimethylammonium formate commerciallyavailable as Dabco® TMR-2 from Evonik Industries;

CATALYST 3: 1,2-dimethylimidazole (DABCO® 2040 from Evonik); CATALYST 4:a formic acid blocked quaternary ammonium salt available as Dabco® TMR-3from Evonik Industries;

ADDITIVE 1: alkyl phosphate flame retardant based onTris(2-chloroisopropyl) phosphate commercially available from ICLIndustrial Products as Fyrol® PCF;

ADDITIVE 2: a reactive bromine-containing diester/ether diol oftetrabromophthalic anhydride commercially available from AlbemarleCorporation as Saytex® RB-79;

HCFO: trans-1,1,1-trifluoro-3-chloropropene, a hydrochlorofluoroolefinblowing agent which has a boiling point of 19° C. that is commerciallyavailable from Honeywell International Inc. as Solstice® LBA; and

ISOCYANATE: a high functionality polymeric diphenylmethane diisocyanate(PMDI) with a NCO content of 30.0 to 31.4% and a viscosity of 610 to 730centipoise at 25° C.

In each case a master batch was prepared by mixing the polyols,catalysts, surfactant, water and blowing agents in the amounts indicatedin Table 1 foams were prepared by mixing the masterbatch with the amountof isocyanate indicated in Table 1 and pouring the mixture into an 83ounce paper cup. The cream time, gel time, tack-free time and free risedensity (FRD) were recorded. Foams were prepared after initiallypreparing the master batch and also after aging the for a minimum of 6days at 60° C. to assess shelf life. Results are set forth in Table 1(reported results represent the average results of three replicateexperiments). N/A indicates that a representative sample was not tested.

Foams were also prepared using a Hennecke HK-1250 high-pressure foammachine. The liquid output was maintained at a constant 27° C. for bothPolyol and Isocyanate side with an output range of 454 to 653grams/second. Foam was shot into a 2′×6′×4″ (61×183×5.1 cm) mold betweenheated platens with a target density of 2.1 pcf (33.6 kg/m³). Theplatens were maintained at 49° C. The foam remained in the mold and wasallowed to cure for 30 minutes at 49° C. before removing. The resultantfoam panels were then tested by an independent laboratory for ASTM E-84classification. A 8″×8′×1″ section of foam was sampled from the panelsand used for k-factor testing according to ASTM C518. Results can beseen in Table 2.

TABLE 1 Example # Component 1 2 3 4 5 6 POLYOL 0 23.95 — — — — — POLYOL1 — 34.25 40.25 24 31 30.5 POLYOL 2 20 13.00 13 6.5 6.5 6 POLYOL 3 9 9 93 3 3 POLYOL 4 — — — 26 28 27 SURFACTANT 1 2.45 2.25 2.25 2.2 — —SURFACTANT 2 — — — — 2.1 2.1 CATALYST 1 1.1 1 1 1.1 1.1 1.1 CATALYST 20.4 0.45 0.45 0.45 0.45 0.45 CATALYST 3 — — — 0.07 0.1 0.1 CATALYST 41.5 — — — — — ADDITIVE 1 12 12 12 11.18 5 5 ADDITIVE 2 12 12 6 8 5 5Water 2.6 2.3 2.3 2 1.75 1.75 HCFO 15 13.75 13.75 15.5 16 18 Total parts100 100 100 100 100 100 ISOCYANATE 152 120 120 116 116 110 Index 150 130130 130 135 135 Cream time (sec) 21 21 25 24 26 27 Gel time (sec) 108113 132 123 120 120 Free Rise Density (kg/m³) 28.5 25.8 30.3 29.6 30.927.7 Polyol shelf life (Days) 12 6 N/A N/A N/A 12

TABLE 2 Example # 1 2 3 4 5 6 Panel Density (kg/m³)   33.6 33.6 33.633.6 33.6 33.6 k- factor @ −5° C.   18.0 18.0 18.0 17.9 18.0 17.4 (mW/m· K) ASTM E84 Flame spread 290* 20 25 15 25 15 index ASTM E84 Smokeindex 600* 800 850 650 400 400 *E-84 test was terminated before thenormal 10 minute period due excessive heat and flame in the tunnelduring the test.

Although the invention has been described in detail in the foregoing forthe purpose of illustration, it is to be understood that such detail issolely for that purpose and that variations can be made therein by thoseskilled in the art without departing from the spirit and scope of theinvention except as it may be limited by the claims.

What is claimed is:
 1. An isocyanate-reactive composition comprising:(a) a polyol blend comprising: (1) an aromatic polyester polyol having afunctionality of 1.5 to less than 2.5 and an OH number of 150 to 360 mgKOH/g; (2) an aromatic polyester polyol having a functionality of atleast 2.5 and an OH number greater than 360 mg KOH/g, which is presentin an amount of at least 10% by weight, based on total weight ofaromatic polyester polyol in the polyol blend; (3) an amine-initiatedpolyether polyol having an OH number of at least 500 mg KOH/g and afunctionality of 2.5 to 4; wherein aromatic polyester polyol is presentin an amount of at least 50% by weight, based on total weight of thepolyol blend; (b) a blowing agent composition comprising: (1) ahydrochlorofluoroolefin; and (2) a carbon dioxide generating chemicalblowing agent; and (c) a tertiary amine catalyst.
 2. Theisocyanate-reactive composition of claim 1, wherein aromatic polyesterpolyol (1) has an OH number of 200 to 335 mg KOH/g and a functionalityof 1.8 to 2.2, and aromatic polyester polyol (2) has an OH number of nomore than 500 mg KOH/g and a functionality of 2.8 to 3.2.
 3. Theisocyanate-reactive composition of claim 1, wherein aromatic polyesterpolyol (1) and aromatic polyester polyol (2) are present in a relativeratio, by weight, of 0.5:1.0 to 2.0:1.0.
 4. The isocyanate-reactivecomposition of claim 1, wherein the amine-initiated polyether polyolcomprises an alkanolamine-initiated polyether polyol present in anamount of 0.1 to 10% by weight, based on total weight of the polyolblend.
 5. The isocyanate-reactive composition of claim 4, wherein thearomatic polyester polyol and the alkanolamine-initiated polyetherpolyol are present in a weight ratio of 10:1 to 50:1.
 6. Theisocyanate-reactive composition of claim 1, wherein the polyol blendfurther comprises a saccharide-initiated polyether polyol having an OHnumber of 200 to 600 mg KOH/g and a functionality of 4 to 6, wherein thesaccharide-initiated polyether polyol is present in an amount of 1 to20% by weight, based on total weight of the polyol blend.
 7. Theisocyanate-reactive composition of claim 6, wherein the ratio, byweight, of aromatic polyester polyol to saccharide-initiated polyetherpolyol in the polyol blend is at least 2:1 and the ratio, by weight, ofsaccharide-initiated polyether polyol to amine-initiated polyetherpolyol in the polyol blend is 0.5:1 to 4:1.
 8. The isocyanate-reactivecomposition of claim 1, wherein the hydrochlorofluoroolefin comprises1-chloro-3,3,3-trifluoropropene present in an amount of 10 to 30% byweight, based on total weight of the isocyanate-reactive composition. 9.The isocyanate-reactive composition of claim 1, wherein the carbondioxide generating chemical blowing agent comprises water present in anamount of 1.0 to 3.0% by weight, based on total weight of theisocyanate-reactive composition and the hydrochlorofluoroolefin andwater are present in an amount of at least 90% by weight, based on totalweight of the blowing agent composition.
 10. The isocyanate-reactivecomposition of claim 1, wherein: (a) the tertiary amine catalystcomposition comprises: (1) 80 to 99% by weight, based on total weight ofthe tertiary amine catalyst composition, of a morpholine; and (2) 1 to20% by weight, based on total weight of the tertiary amine catalystcomposition, of an imidazole; and (b) the isocyanate-reactivecomposition further comprises a trimerization catalyst comprisingquaternary ammonium salt that is present in an amount of from 0.25 to3.0% by weight, based on total weight of the isocyanate-reactivecomposition.
 11. A method of forming a foam, comprising mixing apolyisocyanate with the isocyanate-reactive composition of claim 1 at anisocyanate index of 120 to
 150. 12. A foam-forming reaction mixturecomprising: (a) a polyisocyanate; (b) a polyol blend comprising: (1) anaromatic polyester polyol (I) having a functionality of 1.5 to less than2.5 and an OH number of 150 to 360 mg KOH/g; (2) an aromatic polyesterpolyol (II) having a functionality of at least 2.5 and an OH numbergreater than 360 mg KOH/g, which is present in an amount of at least 10%by weight, based on total weight of the aromatic polyester polyol in thepolyol blend; and (3) an amine-initiated polyether polyol having an OHnumber of at least 500 mg KOH/g and a functionality of 2.5 to 4, whereinaromatic polyester polyol is present in an amount of at least 50% byweight, based on total weight of the polyol blend; (c) a blowing agentcomposition comprising: (1) a hydrochlorofluoroolefin; and (2) a carbondioxide generating chemical blowing agent; and (d) a tertiary aminecatalyst, wherein the reaction mixture has an isocyanate index of 90 to150.
 13. The foam-forming reaction mixture of claim 12, wherein aromaticpolyester polyol (I) has an OH number of 200 to 335 mg KOH/g and afunctionality of 1.8 to 2.2 and aromatic polyester polyol (II) has an OHnumber of no more than 500 mg KOH/g and a functionality of 2.8 to 3.2.14. The foam-forming reaction mixture of claim 12, wherein aromaticpolyester polyol (I) and aromatic polyester polyol (II) are present in arelative ratio, by weight, of 0.5:1.0 to 2.0:1.0.
 15. The foam-formingreaction mixture of claim 12, wherein the amine-initiated polyetherpolyol comprises an alkanolamine-initiated polyether polyol present inan amount of 0.1 to 10%, based upon the total weight of the polyol blendand aromatic polyester polyol and the alkanolamine-initiated polyetherpolyol are present in a weight ratio of at least 10:1.
 16. Thefoam-forming reaction mixture of claim 12, wherein the polyol blendfurther comprises a saccharide-initiated polyether polyol having an OHnumber of 200 to 600 mg KOH/g and a functionality of 4 to 6 that ispresent in an amount of 1 to 20% by weight, based on total weight of thepolyol blend.
 17. The foam-forming reaction mixture of claim 16, whereinthe saccharide-initiated polyether polyol is present in an amount suchthat the ratio, by weight, of aromatic polyester polyol tosaccharide-initiated polyether polyol is at least 2:1 and thesaccharide-initiated polyether polyol and the amine-initiated polyetherpolyol are present in a weight ratio of 0.5:1 to 4:1.
 18. Thefoam-forming reaction mixture of claim 12, wherein thehydrochlorofluoroolefin comprises 1-chloro-3,3,3-trifluoropropene andthe carbon dioxide generating chemical blowing agent comprises water,wherein the hydrochlorofluoroolefin and water are present in an amountof at least 90% by weight, based on total weight of the blowing agentcomposition.
 19. The foam-forming reaction mixture of claim 12, wherein(a) the tertiary amine catalyst comprises: (1) 80 to 99% by weight,based on total weight of the tertiary amine catalyst composition, of amorpholine; and (2) 1 to 20% by weight, based on total weight of thetertiary amine catalyst composition, of an imidazole; and (b) thefoam-forming reaction mixture further comprises a quaternary ammoniumsalt present in an amount of from 0.25 to 3.0% by weight, based on totalweight of the isocyanate-reactive composition.
 20. A foam comprising thereaction product of the foam-forming reaction mixture of claim 12.